7. Project Summary/Abstract Many pathogens continuously evolve to exploit host glycans that are abundantly distributed on target tissues to gain entry and initiate infection. In this class of pathogens is the Influenza A virus (IAV), which continues to pose annual pandemic risks and exerts a heavy financial burden on the US economy. Rapid detection of emerging phenotypic changes in IAV specificity for distinct host glycan classes can provide anearly indication of virus transmissibility and an assessment of infection potential at the onset of an outbreak. Currently, tech- niques that connect a phenotypic adaptation to a direct genomic change are time-, cost- and labor-intensive, causing significant delays in identification of unexpected new viral strains. Such delays may preclude timely production of vaccines and formulation of effective responses by health officials and agencies, often with disas- trous effects. Here we propose a new glycan array platform to rapidly identify genetic alterations underlying distinct shifts in glycan specificity in IAVs in primary isolates. We plan to achieve the high sensitivity required to detect low abundance viruses in these arrays by presenting glycans in synthetic polyvalent ligands with en- hanced avidity toward IAVs and by developing new detection reagents that utilize the activity of viral neurami- dase enzymes for signal amplification. Finally, we will develop microarray substrates that enable the collection and sequencing of captured IAVs based on their unique glycan-binding phenotype. We anticipate that charac- terization of IAV populations driven by their glycan binding phenotype that obviates the need for virus amplifi- cation prior to analysis will provide more efficient and accurate determination of viral strains with increased pandemic risks. The proposed glycan array and detection methods will provide a general tool that could be rapidly extended to other classes of pathogens that utilize glycan interactions to enter their hosts organism.